Data processing device

ABSTRACT

A data processing device includes a read-only memory, a flash memory capable of modifying information stored therein and adding information thereto, a central processing unit performing data processing using information stored in the read-only memory and the flash memory, an information storage area provided in the flash memory for storing predetermined modifiable information among the information used by the central processing unit for data processing, an address storage area provided in the flash memory for storing at least the address of information stored in the information storage area, and an address-modification control unit for, after at least one of modification of modifiable information stored in the information storage area and addition of modifiable information to the information storage area is performed, performing modification of the address of the information stored in the address storage area or addition of the address of the information to the address storage area, whereby the information of the central processing unit used for data processing can be freely modified or added.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a data processing device such asa communication device for performing data processing using a centralprocessing unit (CPU).

[0003] 2. Description of the Related Art

[0004]FIG. 3 shows the construction of a PHS (Personal HandyphoneSystem) 1, which is one example of a data processing device. Otherexamples of data processing devices include portable telephones, copymachines, facsimile machines, and the like.

[0005] The PHS 1 includes a radio frequency unit (RFU) 2, a baseband IC(BBIC) 3, a CPU 4, a flash memory 5, a DTE I/F (Data Terminal EquipmentInterface) 6, and an antenna 7. The CPU 4 has a ROM (Read Only Memory) 8incorporated therein. The mask-programmable type of ROM is widely used.

[0006] The ROM 8 includes at least a main program for the dataprocessing procedure of the CPU 4 and other information such asinformation on functions (subroutine programs) used in the program,information on storage addresses of the functions or storage addressesof variables used in the program, and information on interrupt vectorsfor containing the addresses of interrupt routines of the CPU 4. Theflash memory 5 also includes information for the data processingprocedure. The flash memory is generally slower than ROM, but has theadvantage of being rewritable.

[0007] When the antenna 7 receives a signal, the PHS 1 causes the RFU 2and the BBIC 3 to extract predetermined information (data) from thereceived signal and output it to the CPU 4. The CPU 4 performs dataprocessing based on the extracted information, information stored in theROM 8, and information stored in the flash memory 5.

[0008] When the PHS 1 transmits information, the CPU 4 outputs thedesired information to the BBIC 3. The BBIC 3 and the RFU 2 cause theinformation to modulate a transmission signal and then to be transmittedfrom the antenna 7.

[0009] The ROM 8 is a storage device in which high-speed data access canbe performed. Accordingly, in order to achieve high-speed dataprocessing, the main program for the CPU 4 and information on functions,storage addresses, and the like used in the program are provided in theROM 8.

[0010] However, since the ROM 8 is a read-only storage device,information stored therein cannot be modified. Therefore, the dataprocessing cannot be upgraded in the conventional PHS having the mainprogram and the like stored in ROM, because the main program and thelike cannot be modified.

SUMMARY OF THE INVENTION

[0011] Accordingly, it is an object of the present invention to providea data processing device in which the main program and information onfunctions and the like can be freely modified, thus enabling dataprocessing to be upgraded.

[0012] To this end, according to a first aspect of the presentinvention, there is provided a data processing device including a ROM, aflash memory capable of modifying information stored therein and addinginformation thereto, a CPU performing data processing using informationstored in the ROM and the flash memory, an information storage areaprovided in the flash memory for storing predetermined modifiableinformation among the information used by the CPU for data processing,an address storage area provided in the flash memory for storing atleast the address of the information stored in the information storagearea and an address-modification control unit for, after at least one ofmodification of modifiable information stored in the information storagearea and addition of modifiable information to the information storagearea, and in accordance with said modification of the information oraddition of the information, modifying of the address of the informationstored in the address storage area or addition of the address of theinformation to the address storage area, whereby the information used bythe CPU for data processing can be freely modified or added.

[0013] With the first aspect of the invention, a main program can bestored in ROM while functions and variables to be referenced by the mainprogram can be stored in the flash (rewritable) memory. By providing theaddress storage area in the flash memory and providing theaddress-modification control unit, the address of information can bemodified or added in accordance with modification of the information inthe information storage area or addition of the information thereto.Therefore, the CPU can correctly read the modified information or theadded information, whereby desired modified data processing can beperformed.

[0014] According to a second aspect of the present invention, a dataprocessing device includes a ROM, a flash memory capable of modifyinginformation stored therein and adding information thereto, the CPUperforming data processing using information stored in the ROM and theflash memory, an information storage area provided in the ROM forstoring information used by the CPU for data processing, an addressstorage area provided in the flash memory for storing at least theaddress of predetermined modifiable information among the informationstored in the information storage area, a modified-information storagearea provided in the flash memory for storing modified modifiableinformation, and an address-modification control unit for, after themodified modifiable information is stored in the modified-informationstorage area of the flash memory, and in accordance with themodification of the information, modifying the address of theinformation stored in the address storage area, whereby the informationof the CPU used for data processing can be freely modified or added.

[0015] With the second aspect of the invention, a modified function canbe stored in the flash memory, and the CPU can be controlled to use themodified function for data processing. By providing the informationstorage area and the modified-information storage area in the flashmemory in which information stored therein can be modified andinformation can be added thereto, functions and the like which arestored in the information storage area can be modified or functions andthe like can be added to the information storage area.

[0016] According to a third aspect of the present invention, a dataprocessing device includes a ROM, a flash memory capable of modifyinginformation stored therein and adding information thereto, a CPUperforming data processing using information stored in the ROM and theflash memory, an information storage area provided in the ROM forstoring information used by the CPU for data processing, amodified-information storage area provided in the flash memory forstoring modified predetermined modifiable information among theinformation stored in the information storage area, and aninformation-modification determining unit for determining whethermodified information is stored in the modified-information storage area,wherein, when the information-modification determining unit determinesthat the modified information is stored in the modified-informationstorage area of the flash memory, the CPU is arranged to perform dataprocessing in accordance with the modified information stored in theflash memory instead of information stored in the ROM.

[0017] Generally speaking a CPU operates as follows: (1) detecting apower-on signal; (2) checking hardware; (3) accessing the initialaddress of a main program; (4) fetching and decoding an instruction set;etc. The third aspect of the invention can provide a mechanism fordetermining whether a main program has been modified, which can beexecuted after step (2) mentioned above. Alternatively, thedetermination can be made at a predetermined stage during the executionof the main program.

[0018] With the third aspect of the invention, a modified main programcan be stored in the flash memory, and the CPU can be controlled to usethe modified main program instead of the original main program in theROM. By providing the modified-information storage area in the flashmemory and providing an information-modification determining unit fordetermining whether modified information is stored in themodified-information storage area, when the information-modificationdetermining unit determines that modified information is stored in themodified-information storage area, the CPU is arranged to perform dataprocessing in accordance with the modified information. In addition tomodification of information used for data processing, this arrangementenables the data processing device to perform data processing based onthe modified information.

[0019] As described above, since the data processing device according tothe present invention enables information used for data processing(including a main program, functions, or variables) to be modified oradded, and since desired modified data processing can be correctlyperformed using modified or added information, a data processing devicein which data processing is upgradeable can be provided.

[0020] According to further aspects of the invention, methods areprovided for carrying out the functions of the above-described dataprocessing devices.

[0021] Other features and advantages of the present invention willbecome apparent from the following description of the invention whichrefers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a block diagram showing characteristic main componentsof first and third embodiments of the present invention;

[0023]FIG. 2 is a block diagram showing characteristic main componentsof a second embodiment and the third embodiment of the presentinvention; and

[0024]FIG. 3 is a block diagram illustrating an example of a dataprocessing device.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0025] In FIG. 1, characteristic main components of a PHS, which is oneexample of a data processing device according to a first embodiment ofthe present invention, are shown using solid lines. In description ofthe first embodiment, components that are identical to correspondingcomponents in FIG. 3 have the same reference numerals, and a repeateddescription thereof is omitted.

[0026] The PHS is provided with the construction shown in FIG. 3.Furthermore, the PHS has a construction so that functions used for thedata processing can be modified, the modified functions (not thefunctions before modification thereof) can be correctly read, and dataprocessing can be performed using the modified functions. In accordancewith the above-described modification of the functions, the storageaddresses of variables and interrupt vectors used in the data processingmay be changed. Accordingly, the PHS has a construction to deal withsuch changes of the storage addresses of the variables and changes ofthe interrupt vectors.

[0027] The CPU 4 includes a ROM 8, a data processing unit 9, anaddress-change control unit 10, and an information-writing unit 11. Theflash memory 5 includes an address storage area 12 and a functionstorage area 13 (information storage area). The PHS is further providedwith a RAM (Random Access Memory) 14. The RAM 14 is provided with avariable-storage area 15 for storing at least one variable therein. TheROM 8 is provided with a main-program storage area 16 for storing themain program for performing data processing.

[0028] The address storage area 12 includes an interrupt vector tablearea 12 a for storing at least one interrupt vector therein, a functionaddress table area 12 b for storing at least one function storageaddress therein, and a variable address table area 12 c for storing atleast one variable storage address therein. The function storage area 13stores information for at least one function therein.

[0029] The data processing unit 9 performs data processing in accordancewith the main program stored in the main-program storage area 16 of theROM 8. When data processing is performed, functions or variables areread from the function storage area 13 or the variable-storage area 15by referring to the function addresses or the variable addresses storedin the address storage area 12 of the flash memory 5. In addition,interrupt processing is performed by referring to an interrupt vectorstored in the address storage area 12.

[0030] When it is detected that additional information for a function isbeing input using an information input device 17 such as a keyboard, theinformation-writing unit 11 stores the additional information for thefunction in an unused region of the function storage area 13.

[0031] When a function stored in the function storage area 13 is desiredto be modified and when information for the modified function is inputusing the information input device 17, the information-writing unit 11detects the input of the information for the modified function and thenstores the information for the modified function in the function storagearea 13 using either of the following two methods. According to a firstmethod, the information-writing unit 11 overwrites the original function(the function to be modified) with the modified function; and accordingto a second method, the information-writing unit 11 stores the modifiedfunction in a location (an unused region) whose address is differentfrom that of the original function).

[0032] When the additional information for the function is stored in thefunction storage area 13, when the modified function is stored at adifferent location from the original function, or when the storageaddresses of the variables used for the function are changed inaccordance with modification or addition of the function, it isnecessary to appropriately modify address information in the addressstorage area 12 or add address information to the address storage area12, so that the modified function, the added function, or a desiredvariable can be correctly read.

[0033] In the first embodiment, the address-change control unit 10 isprovided to avoid the foregoing problem. For example, when detectingthat address information for related functions or related variableswhich are modified or added in accordance with modification or additionof the function is input using the information input device 17, theaddress-change control unit 10 determines whether the input addressinformation is for modification of only the added or modified part ofthe address storage area 12, or for modification of the entiretythereof.

[0034] When it determines that the input address information is formodification of only the modified part, the address-change control unit10 causes the information-writing unit 11 to overwrite a modificationaddress (the information address to be modified) stored in the addressstorage area 12 with the input address information. Alternatively, theinformation-writing unit 11 stores the input address information in anunused region of the address storage area 12.

[0035] When it determines that the input address information is formodification of the entirety of the address storage area 12, theaddress-change control unit 10 causes the information-writing unit 11 tomodify the contents of the entirety of the address storage area 12 withthe input address information.

[0036] When information for modification or addition of an interruptvector is input using the information input device 17 to modify or addthe interrupt vector, the address-change control unit 10 determineswhether the input address information is for modification of only theadded or modified part of the address storage area 12 or formodification of the entirety thereof. Based on the determination, theaddress-change control unit 10 causes the information-writing unit 11 toadd the interrupt vector to the address storage area 12, modify themodification interrupt vector in the address storage area 12 with theinput interrupt vector, or modify all information in the address storagearea 12 with the input address information.

[0037] In the first embodiment, since the function storage area 13 isprovided in the flash memory 5 in which information can be freely addedor modified, the functions stored in the function storage area 13 can beadded or modified.

[0038] Since the address storage area 12 is provided in the flash memory5 and the address-change control unit 10 is provided in the CPU 4,modification or addition of the addresses of related functions used forthe function, or modification or addition of the addresses of relatedvariables used for the function can be performed in accordance with themodification or addition of the function. This construction can avoidthe foregoing problem in which, although modification or addition of thefunction is performed, the modified or added function cannot becorrectly read, so that data processing cannot be correctly performed.

[0039] Since the interrupt vector table area 12 a is provided in theaddress storage area 12 of the flash memory 5, an interrupt vector canbe modified or added when necessary.

[0040] As described above, since the first embodiment is provided withthe construction in which the functions used in the data processing canbe freely added or modified, the addresses of the related functions orthe addresses of the related variables can be freely added or modifiedin accordance with modification or addition of the function, and theinterrupt vector also can be freely modified or added, the dataprocessing device can perform a desired modified data processing. Inother words, a data processing device can be provided in which dataprocessing thereof is upgradeable.

[0041] A second embodiment of the present invention is described. In thedescription of the second embodiment, components that are identical tocorresponding components in the first embodiment have the same referencenumerals, and a repeated description thereof is omitted.

[0042] Characteristic features of the second embodiment, whichdistinguish it from the first embodiment, are represented by solid linesin FIG. 2. That is, a function storage area 20 (information storagearea) for storing functions is provided in the ROM 8 and, instead of thefunction storage area 13, a modified-function storage area 21(modified-information storage area) is provided in the flash memory 5.Otherwise, the construction of the second embodiment is substantiallyidentical to that of the first embodiment.

[0043] When it detects that information for a modified or an addedfunction is being input using the information input device 17, theinformation-writing unit 11 stores the modified or the added function inthe modified-function storage area 21. When the modified function isstored in the modified-function storage area 21, the input modifiedfunction may be overwritten on the modification function stored in themodified-function storage area 21, or the input modified function may bestored in a location whose address is different from that of themodification function.

[0044] As described above, when the function is modified or added andthen when addresses stored in the address storage area 12 are notchanged after modification or addition of the function, a problem suchas a failure in reading the modified or added information arises.Accordingly, in order to positively avoid this problem, theaddress-change control unit 10 modifies or adds the correspondingaddresses stored in the address storage area 12 in the same manner as inthe first embodiment.

[0045] In the second embodiment, the function storage area 20 isprovided in the ROM 8 (read only) and the modified-function storage area21 is formed in the flash memory 5 (re-writable). By storing theinformation for the modified or added function in the modified-functionstorage area 21, the modified or added function can be held in the dataprocessing device. Furthermore, since the address-change control unit 10is provided, it can modify or add the address of a function stored inthe address storage area 12 in accordance with modification or additionof the function, so that the modified or added function can be correctlyread from the modified-function storage area 21.

[0046] Furthermore, the functions which are not to be modified arearranged to be read from the function storage area 20 of the ROM 8.Since data stored in the ROM 8 can be read faster than data stored inthe flash memory 5, compared to a case in which all functions are readfrom the flash memory 5, high-speed data processing can be performed byreading the unmodified functions from the ROM 8.

[0047] A third embodiment of the present invention is described. In thedescription of the third embodiment, components that are identical tocorresponding components in the foregoing embodiments have the samereference numerals, and a repeated description thereof is omitted.

[0048] Characteristic features of the third embodiment are representedusing dashed lines in FIGS. 1 and 2. That is, a modified-main-programstorage area (modified-information storage area) 22 is formed in theflash memory 5 and a main-program-modification determining unit 23 isprovided in the CPU 4. Otherwise, the construction of the thirdembodiment is substantially identical to those of the foregoingembodiments.

[0049] In the third embodiment, when the main program stored in themain-program storage area 16 of the ROM 8 is desired to be changed, amodified main program is input by the information input device 17. Afterdetection of the input of the modified main program, theinformation-writing unit 11 stores the modified main program in themodified-main-program storage area 22. At this time, a flag Frepresenting storage of the modified main program is set in themodified-main-program storage area 22.

[0050] In accordance with a main-program-modification determininginstruction output from the data processing unit 9, themain-program-modification determining unit 23 determines, based on theflag F, whether the modified main program is stored in themodified-main-program storage area 22.

[0051] In the third embodiment, the data processing unit 9 outputs themain-program-modification determining instruction at a predeterminedtiming which is preset by the main program in the ROM 8. For example, inorder to provide for modification of the entirety of the main program inthe ROM 8, the main program stored in the ROM 8 is programmed so thatthe main-program-modification determining instruction is output at thebeginning of the main program.

[0052] In this case, the data processing unit 9 outputs themain-program-modification determining instruction in accordance with themain program in the ROM 8 and the main-program-modification determiningunit 23 determines in accordance with the instruction whether the mainprogram has been modified. When the data processing unit 9 detects,based on the determination, that there is a modified main program storedin the modified-main-program storage area 22, data processing isperformed in accordance with the modified main program stored in themodified-main-program storage area 22 instead of the main program storedin the ROM 8.

[0053] In order to provide for partial modification of the main programin the ROM 8, the main program stored in the ROM 8 is programmed so thatthe main-program-modification determining instruction is output at thebeginning of at least one modifiable program part at a predeterminedlocation in the main program.

[0054] In this case, before executing the at least one modifiableprogram part, the data processing unit 9 causes themain-program-modification determining unit 23 to determine whether themain program has been modified. When the data processing unit 9 detects,based on the determination, that there is a modified program which is amodification of the modifiable program part in the ROM 8 stored in themodified-main-program storage area 22, data processing is performed inaccordance with the modified program stored in the modified-main-programstorage area 22 instead of the main program stored in the ROM 8. Afterprocessing is performed in accordance with the modified program, thedata processing unit 9 returns to processing in accordance with the mainprogram stored in the ROM 8.

[0055] In this third embodiment, since, in addition to the sameconstruction as in the foregoing embodiments, the modified-main-programstorage area 22 is provided, the main program can be modified, not tomention that the function and the address information can be modified oradded in the same manner as in the foregoing embodiments. Since themain-program-modification determining unit 23 is provided, when themodified main program is input, data processing can be performed, basedon the determination of the main-program-modification determining unit23, in accordance with the modified main program instead of the mainprogram stored in the ROM 8. The problem of data processing beingperformed in accordance with the main program stored in the ROM 8 evenafter the modified main program is input can be avoided.

[0056] The present invention is not limited to the foregoingembodiments. Other embodiments of the invention may take various forms.For example, although the ROM 8 is provided in the CPU 4, it may beprovided outside the CPU 4. In each embodiment, the interrupt vectortable area 12 a, the function address table area 12 b, and the variableaddress table area 12 c are provided in the address storage area 12.However, when change of the interrupt vector is not needed, theinterrupt vector table 12 a does not need to be provided. In addition,when modification and addition of variable addresses are not needed, thevariable address table area 12 c does not need to be provided.

[0057] In the first and second embodiments, although only a function isdescribed as being modifiable information, information other than thefunction may be modified. In this case, an area for the otherinformation may be provided in the address storage area 12.

[0058] In the second embodiment, when a function stored in the functionstorage area 20 in the ROM 8 is modified and the modified function isstored in the modified-function storage area 21 of the flash memory 5,the modified function is arranged to be correctly read by replacing theoriginal address (which may be stored in the ROM 8) of the modificationfunction, with a new address of the modified function. The modifiedfunction may be arranged to be correctly read by providing the followingconstruction.

[0059] For example, a modified-function address table area, for storingthe addresses of the functions stored in the modified-function storagearea 21, is provided in the address storage area 12, and amodified-function determining unit (modified-information determiningunit) is provided for determining whether there is a modified functionstored in the modified-function storage area by referring to themodified-function address table area. The main program stored in the ROM8 is programmed so that a modified-function determining instruction isoutput before the function is read.

[0060] Therefore, while data processing is performed in accordance withthe main program stored in the ROM 8 before the function is read, thedata processing unit 9 causes the modified-function determining unit todetermine whether there is a modified function stored in themodified-function storage area 21. When the data processing unit 9detects, based on the determination, that the modified function isstored in the modified-function storage area 21, data processing isperformed using the modified function instead of the function stored inthe function storage area 20 of the ROM 8. Thus, this alternativeconstruction enables the modified function to be correctly read.

[0061] In the foregoing embodiments, an example in which the PHS is thedata processing device is described. However, the present invention isnot limited to the PHS and can be applied to any device provided with afunction performing data processing. For example, the present inventioncan be applied to a communication device such as a portable telephoneother than the PHS, a data processing device other than a communicationdevice, and the like.

[0062] Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.Therefore, the present invention is not limited by the specificdisclosure herein.

What is claimed is:
 1. A data processing device comprising: a read-onlymemory; a flash memory capable of modifying information stored thereinand adding information thereto; a central processing unit performingdata processing using information stored in said read-only memory andsaid flash memory; an information storage area provided in said flashmemory for storing predetermined modifiable information among theinformation used by said central processing unit for data processing; anaddress storage area provided in said flash memory for storing at leastthe address of the information stored in said information storage area;and an address-modification control unit for, after at least one ofmodification of modifiable information stored in said informationstorage area and addition of modifiable information to said informationstorage area, and in accordance with said one of the modification of theinformation and addition of the information, performing one ofmodification of the address of the information stored in said addressstorage area and addition of the address of the information to saidaddress storage area, whereby the information used by said centralprocessing unit for data processing can be freely modified or added. 2.A data processing device comprising: a read-only memory; a flash memorycapable of modifying information stored therein and adding informationthereto; a central processing unit performing data processing usinginformation stored in said read-only memory and said flash memory; aninformation storage area provided in said read-only memory for storinginformation used by said central processing used for data processing; anaddress storage area provided in said flash memory for storing at leastthe address of predetermined modifiable information among theinformation stored in said information storage area; amodified-information storage area provided in said flash memory forstoring modified modifiable information; and an address-modificationcontrol unit for, after the modified modifiable information is stored insaid modified-information storage area of said flash memory, and inaccordance with the modification of the information, modifying theaddress of the information stored in said address storage area, wherebythe information of said central processing unit used for data processingunit can be freely modified or added.
 3. A data processing devicecomprising: a read-only memory; a flash memory capable of modifyinginformation stored therein and adding information thereto; a centralprocessing unit performing data processing using information stored insaid read-only memory and said flash memory; an information storage areaprovided in said read-only memory for storing information used by saidcentral processing unit for data processing; a modified-informationstorage area provided in said flash memory for storing modifiedpredetermined modifiable information among the information stored insaid information storage area; and an information-modificationdetermining unit for determining whether modified information is storedin said modified-information storage area, wherein, when saidinformation-modification determining unit determines that the modifiedinformation is stored in said modified-information storage area of saidflash memory, said central processing unit is arranged to perform dataprocessing in accordance with the modified information stored in saidflash memory instead of information stored in said read-only memory. 4.A method in a data processing device comprising: a read-only memory; aflash memory capable of modifying information stored therein and addinginformation thereto; a central processing unit performing dataprocessing using information stored in said read-only memory and saidflash memory; an information storage area in said flash memory; and anaddress storage area in said flash memory; said method comprising thesteps of: storing in said information storage area predeterminedmodifiable information among the information used by said centralprocessing unit for data processing; storing in said address storagearea at least the address of the information stored in said informationstorage area; performing at least one of modification of modifiableinformation stored in said information storage area and addition ofmodifiable information to said information storage area; and then, inaccordance with said one of modification of the information and additionof the information, performing one of modification of the address of theinformation stored in said address storage area and addition of theaddress of the information to said address storage area, whereby theinformation used by said central processing unit for data processing canbe freely modified or added.
 5. A method in a data processing devicecomprising: a read-only memory; a flash memory capable of modifyinginformation stored therein and adding information thereto; a centralprocessing unit performing data processing using information stored insaid read-only memory and said flash memory; an information storage areain said read-only memory; an address storage area in said flash memory;and a modified-information storage area in said flash memory; saidmethod comprising the steps of: storing in said information storage areainformation used by said central processing unit for data processing;storing in said address storage area at least the address ofpredetermined modifiable information among the information stored insaid information storage area; storing modified modifiable informationin said modified-information storage area; and after the modifiedmodifiable information is stored in said modified-information storagearea of said flash memory, and in accordance with the modification ofthe information, modifying the address of the information stored in saidaddress storage area, whereby the information of said central processingunit used for data processing unit can be freely modified or added.
 6. Amethod in a data processing device comprising: a read-only memory; aflash memory capable of modifying information stored therein and addinginformation thereto; a central processing unit performing dataprocessing using information stored in said read-only memory and saidflash memory; an information storage area in said read-only memory; anda modified-information storage area in said flash memory; said methodcomprising the steps of: storing in said information storage areainformation used by said central processing unit for data processing;storing, in said modified-information storage area, modifiedpredetermined modifiable information among the information stored insaid information storage area; determining whether modified informationis stored in said modified-information storage area; and when saidmodified information is stored in said modified-information storage areaof said flash memory, performing data processing in said centralprocessing unit in accordance with the modified information stored insaid flash memory instead of information stored in said read-onlymemory.